1. Field of the Invention
The present invention relates to an unused band use right acquisition controlling method and a passive optical network for the same.
2. Description of the Related Art
An ATM (Asynchronous Transfer Mode) network is conventionally known which is used as a root technique of a B-ISDN. Also, as one of an optical subscriber system network which links between the ATM network and a terminal of a user, a PON (Passive Optical Network) is known.
The passive optical network (PON) is installed in a station of the NTT, for example, and an optical line termination (OLT) and an optical network unit (ONU) are connected with the ATM network are connected by an optical fiber. At this time, the route of the optical fiber is branched on the way by a star coupler and a plurality of optical network units (ONUs) are connected to one optical line termination (OLT).
By the way, in ITU-T G.983 which is the standards to prescribe an interface with the optical subscriber in the ATM network, a band in the upstream direction (direction from the optical network unit (ONU) to the optical line termination (OLT)) is determined in accordance with an instruction from the optical line termination (OLT). However, in a usual operation, there is a band which is not used by each optical network unit (ONU).
Conventionally, there is a problem that effective use is not made, because the unused band is used only when the band use capacity of other optical network units (ONUs) increases or optical network unit (ONU) is added.
In conjunction with the above description, an optical communication apparatus is disclosed in Japanese Laid Open Patent application (JP-A-Heisei 11-98151). In this example, the optical communication equipment carries out optical communication using an upstream channel and a downstream channel which are provided between a subscriber terminal apparatus and a station apparatus. A transmitting section is provided in the station apparatus of the optical communication apparatus to transmit a subscriber ID and a polling instruction to the subscriber terminal apparatus based on predetermined subscriber data. The sending-out section sends out a transmission request transmitted from the subscriber terminal apparatus and a transmission permission signal to a shared band in the upstream channel which is preset in case of the reception of the subscriber ID to the subscriber terminal apparatus, in response to the polling instruction. A calculating section calculates the packet length of a packet signal transmitted from the subscriber terminal apparatus in response to the transmission permission signal. A control section controls the sending-out section to send out the transmission permission signal for the time determined based on the packet length calculated by the calculating section.
Also, a cell delay change restraint band setting apparatus is elucidated to Japanese Laid Open Patent application (JP-A-Heisei 11-187037). In the cell delay change restraint band setting apparatus of this reference, an input unit inputs a combination of remote device numbers of a plurality of remote units, the number of cell allocations in a band management frame and an offset of each cell allocation and a magnification value. An ideal band setting calculation processing section calculates the number of empty cells in the band management frame from a combination of the remote device numbers and the number of cell allocations in the band management frame, and determines the existence or non-existence of the cell allocation to each of the remote units. The ideal band setting calculation processing section divides the band management frame by the number of cell allocations when there is the cell allocation, multiplies the dividing result by the magnification value and calculates a temporary ideal cell interval. The ideal band setting calculation processing section stores in an ideal band table as a cell sending-out number, a value of the integral part of a value obtained by dividing the offset value by the magnification value. The ideal band setting calculation processing section carries out the above processing for all cell allocations and for all the remote units to store as an ideal band table group. An allocation processing section extracts the cell sending-out numbers of some allocation cell from the ideal band table group and arranges them in the ascending order. The allocation processing section repeats this processing for all the remote units and produces tables in which the extracted cell sending-out numbers are arranged. The allocation processing section searches the existence or non-existence of the cell allocation in the ascending order, and executes the allocation processing to arrange the remote unit number of the cell allocation in a band setting table in order. The allocation processing section executes this processing to all of the tables.
Also, a method of transmitting an ATM cell through a passive optical network is disclosed in Japanese Laid Open Patent application (JP-A-Heisei 11-215146). In this reference, an ATM cell is transmitted from the ATM network to a light network apparatus in the passive light network connected with the ATM network. An optical subscriber apparatus interposed between the ATM network and the passive light network operates:                a. to store a light network device identification data which specifies the light network apparatus as the object of unicast, and a cryptography key corresponding to the light network apparatus, and to store an emulated local area network identification data specifying each group of the light network apparatuses as the object of the multicast and a cryptography key corresponding to the group,        b. when the broadcast of the ATM cell to all the light network apparatuses connected with the passive light network, to add an identification data indicative of the broadcast to the ATM cell as the light network device identification data and send out to the passive light network as an ATM passive optical network (PON) frame,        c. when carrying out the multicast of the ATM cell to the light network apparatuses of a specific group connected with the passive light network, to add the emulated local area network identification data specifying the group to this ATM cell and then to carry out cryptography processing based on the cryptography key corresponding to the group, to add an identification data indicative of the multicast as the light network device identification data and to send out to the passive light network as the ATM passive optical network (PON) frame, and        d. when carrying out the unicast of the ATM cell to the specific light network apparatus connected with the passive light network, to carry out cryptography processing based on the cryptography key corresponding to the light network apparatus to the ATM cell, and to add the light network device identification data specifying the light network apparatus to the ATM cell, and then to send out to the passive light network as the ATM passive optical network (PON) frame. Each light network apparatus connected with the passive light network operates:        e. to store the cryptography key for the unicast used when the unicast is carried out to the light network apparatus, and to store the cryptography key for the multicast used when the multicast is carried out to each group of the light network apparatuses as the object of the multicast,        f. when the ATM passive optical network (PON) frame arrived through the passive light network contains the light network device identification data corresponding to the light network apparatus, to unicast receive the ATM cell contained in the ATM passive optical network (PON) frame using the cryptography key for the unicast corresponding to the light network apparatus,        g. when the ATM passive optical network (PON) frame which arrived through the passive light network contains the identification data indicative of the broadcast as the light network device identification data, to broadcast receives the ATM cell contained in the ATM passive optical network (PON) frame, and        h. when the ATM passive optical network (PON) frame which arrived through the passive light network contains the identification data indicative of the multicast as the light network device identification data, to multicast receive the ATM cell contained in the ATM passive optical network (PON) frame using each cryptography key set for every group.        
Also, a band change setting method is disclosed in Japanese Laid Open Patent application (JP-A-Heisei 11-355301). In the band change setting method of this reference, a plurality of subscriber apparatuses are connected with a same line and an in-station apparatus and each subscriber apparatus carry out bidirectional communication. The subscriber apparatus produces a data cell when the upstream data to the in-station apparatus exists, and produces a dummy cell when the upstream data does not exist. The subscriber apparatus sends out the produced cell to the in-station apparatus in accordance with an upstream signal sending-out timing sent out from the in-station apparatus. The in-station apparatus counts the dummy cells and data cells received from each subscriber apparatus every subscriber apparatus. The in-station apparatus carries out a resetting operation of the band allocation to reduce the allocated band to the subscriber apparatus when there are many dummy cells, and to increase the allocated band to the subscriber apparatus within a predetermined upper limit value when there are many data cells. Thus, the in-station apparatus sends out the upstream signal sending-out timing determined based on this resetting operation to each subscriber apparatus.
Also, an optical communication channel switching system is disclosed in Japanese Laid Open Patent Application (JP-A-2000-4461). In this reference, a crossing connection apparatus (XC) previously stores channel data corresponding to the band change setting due to the addition or removal of a subscriber apparatus (19 to 21). The channel termination apparatus (17a, 17b) carries out the band change setting of a transmission capacity and phase due to the addition or removal of a subscriber apparatus (19 to 21) based on band change data (S16) from a channel switching control section (18). Moreover, the channel termination apparatus notifies the band change setting to the crossing connection apparatus (XC) at the same time. In response to this notice, the crossing connection apparatus (XC) carries out based on the stored channel data the channel change without temporal down during the operation such that the TDMA time slots are changed in accordance with the band change setting due to the addition or removal of the subscriber apparatus (19 to 21) by the channel termination apparatus (17a, 17b).